1. Field of the Invention
The present invention relates to an adjustable nozzle assembly comprising only two pieces for mounting to a trigger sprayer which is used in dispensing liquids and more particularly to a nozzle assembly including only a unitary nose bushing which is made of a relatively hard plastic material and a nozzle cap which is also made of a relatively hard plastic material and which is axially adjustable on the nose bushing between an OFF mode position, a SPRAY mode position and a STREAM mode position.
2. Description of the Related Art Including Information Disclosed under 37 CFR .sctn..sctn. 1.97-1.99
Heretofore, various nozzle assemblies for a trigger sprayer have been proposed which are adjustable to provide varying discharge patterns, i.e. a spray pattern and a stream pattern.
Examples of analogous and non-analogous prior art adjustable nozzle assemblies for selectively dispensing a liquid in a spray or stream mode, are disclosed in the following U.S. Patents, Japanese published patent applications, PCT published patent application and Taiwanese published patent applications:
______________________________________ U.S. Pat. No. Patentee ______________________________________ 3,967,765 Micallef 4,220,285 Gualdi 4,313,569 Burke 4,503,998 Martin 4,640,444 Bundschuh 4,911,361 Tada 4,991,778 Maas 5,234,166 Foster et al. Japanese Patent Application No. Applicant ______________________________________ 57-192 076 Canyon Corporation 59-36177 Canyon Corporation PCT Publication No. Applicant ______________________________________ WO 92/07660 Foster et al. Taiwanese Patent Application No. Applicant ______________________________________ 81101823 Thomann 82211671 Chang ______________________________________
The Maas et al. U.S. Pat. No. 4,991,778 discloses an adjustable nozzle assembly for a trigger sprayer comprising a nose bushing and a nozzle cap which is screwed on the nose bushing. The nozzle cap has a discharge orifice in a front face and a flanged skirt extending from a front wall thereof. The flanged skirt is threaded inside a rear portion thereof and an internally specially contoured stepped surface is located forwardly of the threads to provide reduced diameter, annular surfaces at two locations rearward of an inner face of the front wall of the cap.
The nozzle cap is selectively threadably positionable on the nose bushing between three selected positions such that positioning of the inner wall surface and the inner annular surfaces of the nozzle cap flange skirt selectively cooperate with a front face and an annular periphery of a nose bushing face disk having two angular grooves in the annular periphery thereby selectively to provide a stop mode position for containment of liquid, a spray mode position to discharge liquid in a spray pattern and a stream mode position to discharge liquid in a stream pattern from the discharge orifice.
The Foster et al. U.S. Pat. No. 5,234,166 discloses a spinner assembly for a sprayer. The spinner assembly is fitted to a discharge nozzle or nose bushing and includes an annular chamber surrounding a central post having a swirl chamber at an outer end thereof. A nozzle cap variably engages the discharge nozzle and has a central projection on an inner side of a front wall thereof and an annular groove defined by a shoulder surrounding the central projection. The central projection can seal against the floor and/or annular wall of the swirl chamber and the annular groove can seal over the annular wall.
Japanese Published Patent Application No. 57-192 076 discloses a dispenser having a cylindrical spinner, a nozzle cap and a nozzle base. The spinner is located at an end of the nozzle base. The nozzle base has an annular wall at an end thereof having an inner circumferential surface. A projection on the inside of the spinner is received within and seals against the inner circumferential surface of the annular wall of the nozzle base. A swirl chamber is formed in the area between the projection on the inside of the nozzle cap and a front wall of the spinner.
Japanese Published Patent Application No. 59-361 77 discloses a spinner assembly which is integral with an annular section of a bushing and is fitted over an open end of a piston. The spinner has a base portion with apertures therethrough which open into a diverging annular passageway defined between a center post of the spinner, which appears to taper inwardly and forwardly so as to have a partially conical shape, and an outer flange or spinner body which tapers outwardly to form an annular chamber which is larger in cross section than the apertures. The spinner head post has an annular wall at an end thereof and the annular wall has a passage therethrough communicating with a swirl chamber.
A nozzle cap receives the annular wall at the downstream end of the spinner head with an inner circumferential surface of the annular wall sealing against a peripheral section of a projection extending inwardly from the back side of the nozzle cap. The projection is ring shaped and seals in an annular groove in the bottom of the swirl cavity at the downstream end of the post of the spinner head. The annular groove has a partially cylindrical section that meets with a rounded end of the projection or annular section.
Heretofore difficulties have been encountered in manufacturing an adjustable threaded nozzle cap and nose bushing assembly. These difficulties center around two problems, they being: 1) how to maintain a liquid seal between the nozzle cap and the nose bushing and 2) how to provide ease or relative rotation or turning of the nozzle cap on the nose bushing.
When using hard plastic materials, it is difficult to create matching sealing surfaces which will not leak over time particularly in the case where the hard mating surfaces of the rigid plastic parts are formed by injection molding. This difficulty is complicated by the fact that plastic parts in confinement take on a "set" and, as a result of the "set", they do not maintain their original assembled position and this eventually leads to leaking of fluid between mating plastic parts in a nozzle assembly.
It has been found to be difficult and complicated to meet the requirement of having two assembled hard rigid plastic parts that can be rotated reasonably easily with respect to each other by hand when trying to meet the objective of creating and maintaining a liquid seal between mating hard plastic surfaces. In other words, as you attempt to make the fit between the hard sealing surfaces a tight interference fit to create a liquid seal, the mating hard rigid plastic parts often fit so tightly that they cannot rotate easily between each other.
The objective of providing a good liquid seal between hard plastic parts in a nozzle assembly and yet have ease of rotation between the nozzle cap and other parts of the assembly has been achieved in the past by providing more than two parts, namely by adding a third part, and by making the third part of a softer material, such as out of polyethylene or EVA. The part made of this softer plastic material, although it takes a set, retains a memory of its original molded construction and together with lip seals formed therein easily will make a good seal with a hard plastic part over a short period of time. The softness of the additional part also allows for ease of rotation of a nozzle cap relative to the softer plastic part.
For example, in the Burke U.S. Pat. No. 4,313,569 a nozzle cap threaded to the barrel of a pump can easily rotate relative to a nozzle seal having an annular sealing lip which is positioned between the pump barrel and the nozzle cap and which is made of a softer plastic material than the nozzle cap.
In a similar manner, the Martin U.S. Pat. No. 4,503,998 provides an elastic cup member positioned between a nozzle cap and a nose bushing having a cavity which receives a channel-defining insert which cooperates with the elastic cup member and the nozzle cap to control the output of a trigger operated pump.
In the Maas et al. U.S. Pat. No. 4,991,778, a rubber O-ring creates a seal between a nozzle cap made of polypropylene and a nose bushing made of polypropylene.
Further, the Foster et al. U.S. Pat. No. 5,234,166 teaches the provision of a separate one piece spinner assembly made of a soft plastic material and having a spinner head at an outer end thereof that engages a projection that extends rearwardly from the inner surface of a front wall of a nozzle cap made of a harder plastic material. The spinner assembly, and particularly a spring and valve portion thereof, are received in a nozzle fluid chamber in a nose bushing/nozzle on which the nozzle cap is threadedly received.
As will be described in greater detail hereinafter, the two piece nozzle assembly of the present invention provides sealing between and ease of relative rotation between only two hard plastic parts, they being a nozzle cap and an integral unitary nose bushing, without the need of a third part made of a softer plastic material.